This invention relates to a ring binder mechanism for securing loose-leaf papers.
A typical ring binder mechanism has a sheet metal housing which is longitudinally stiff, but laterally flexible, and contains a pair of blades which are hinged along mating edges. Each blade supports a number of ring halves. The blades have a combined width slightly greater than the width of the housing, so that they toggle between two extreme positions, in one of which the tips of the ring halves meet, forming closed rings, and in another of which the ring halves are open, allowing one to insert or remove loose-leaf papers.
As ring binder users know, the rings can pinch a finger painfully when they snap shut. Prior constructions do not keep one from accidentally getting a finger between the ring ends when closing the ring binder mechanism.